Polymeric (e.g., polycarbonate) sheet material is commonly used in rail and aircraft applications, e.g., in seats or cladding applications. These applications typically require that stringent fire safety requirements are met such as flame retardance, smoke density, smoke toxicity, and heat release. Polymeric materials such as polycarbonate have difficulty meeting heat release requirements for aircraft and rail applications and often have to be combined with other, more expensive materials, to pass the aircraft and rail application tests. Various requirements have been placed on the flame retardance, smoke density, smoke toxicity, and heat release properties of the sheet materials used in the construction of interior panels and parts for aircraft and rail applications.
Lightweight polymeric sheets and products derived therefrom have achieved a considerable and significant commercial success in a number of fields. These lightweight sheets have been employed in aircraft and other structures for insulation and structural purposes. The electronics and appliance industry uses polymer foams for electrical and thermal insulation and for structural purposes. Aircraft interior components currently utilize low density foamed and honeycomb structure materials. These materials provide excellent stiffness and low weight, but are difficult to thermoform and require additional lamination of other sheet and/or film materials to produce a sheet with an aesthetic surface.
Multilayer sheets that can meet or exceed the various fire safety requirements (e.g., in rail and/or aircraft applications), are desired in the industry. Additionally, multilayer sheets that can meet or exceed the various fire safety requirements in transportation interior applications; that can be thermoformed without an adverse effect on adhesion or heat stability of the layers of the multilayer sheet; and have low gloss levels for minimizing light reflection, are also desired.
Thus, there is a need for lightweight polymeric sheets that can be thermoformed and that do not require additional lamination of other sheets/films to produce a sheet with a functional purpose of, for example, reducing overall weight, improved fire safety, and/or have an aesthetic surface.